Cold Engine Driveability

Set to specifications: Accelerator pump travel, engine idle speed, throttle positioner setting, timing, A/C idle-up speed and throttle position switch setting.

Figure 1 - View on R.H. side of carburetor:

The procedures for these settings are detailed below:

- ACCELERATOR PUMP TRAVEL - engine not running

(A). Remove air cleaner assembly.
(B). Ensure the choke valve is fully open.
(C). Unscrew idle speed adjusting screw until throttle
valve is fully closed.
(D). Unscrew throttle positioner screw (TP screw)
until it is fully disengaged (see Figure 1).
(E). Measure accelerator pump stroke at top of the
pump plunger and adjust by bending rod if necessary per specifications below:

1985 Model Year: 4 mm (.158 inches)
1986 Model Year: 2 mm (.079 inches)

(F). Reset idle speed screw to approximate original
location.
(G). Reinstall air cleaner assembly.
- ENGINE IDLE SPEED

With engine warmed up to normal operating temperature, all electrical loads switched off and engine running, except where indicated, make adjustments in the following order.

- ENGINE TIMING

Following appropriate underhood label instructions set timing to no more than 7 degrees B.T.D.C.

- THROTTLE POSITIONER SETTING

Reference section 6E14-24 for the relevant model year in the Nova Shop Manual.

Figure 2 - View on R.H. side of carburetor:

- AIR CONDITION IDLE UP SETTING

Where applicable adjust air conditioning idle up setting screw (See Figure #2) to 950 plus or minus 50 RPM with air conditioner compressor running, engine cooling fan not running.

Figure 3 - L.H. suspension strut tower:

THROTTLE POSITION SWITCH (TPS) SETTING (1986/1987 only)
(A). Disconnect and plug the canister purge vacuum hose at the vacuum switching valve (VSV) located on the left front strut tower underhood (See Figure #3) and plug VSV outlet.

(B). Disconnect vacuum hose from the "M" port of the thermostatic vacuum switching valve (TVSV) and plug "M" port.

Figure 4 - R.H. side dash-upper under hood:

(C). Disconnect green electrical connector (TP switch) located on the upper dash panel at the right hand side underhood. (See Figure #4)

(D). Connect tachometer.

(E). Connect OHM meter between "TPS" connector terminal (to carburetor) and ground.

Figure 1 - View on R.H. side of carburetor:

(F). With Engine running at idle, slowly increase idle speed by opening throttle to 1600 RPM. OHM meter should register open circuit. If OHM meter shows a closed circuit (continuity) adjust "TP" switch adjusting screw to give an open circuit (See Figure #1).
(G). Continue to increase engine speed to 2000 RPM. OHM meter should now register a closed circuit (continuity). If open circuit is shown adjust "TPS" setting screw to obtain a closed circuit.

(H). Increase engine idle speed to 2500 RPM and release to return engine speed to base idle.

(I). Repeat steps "F" thru "H" to check settings. Make further adjustments if necessary until switch is adjusted to ensure that the "TPS" switch closes between 1600 and 2000 RPM.